I know this is not exactly what you asked for, however it may give you
what you want with a permanent effect. This is a line of paper by the
name of:
Bee Vellum - it is availiable in a variety of thicknesses.
For Pt/Pd prints, I have evaluated it as:
Great quality with a lot of depth and substance.
Excellent detail in print.
Excellent luminosity from translucency, several thicknesses are
available.
Translucent, color of print may be changed by colored under mat.
Average to coat, but watch for curling.
Jeff